Below are some examples of
Question: What was the first use of spacecraft thermal control louvers, doors, pinwheels, or other things that physically actuate either passively or actively?
I just ran across the louvers in close-up view!
In the JLP video 1965: Discovery at Mars there is an excellent video The Changing Face of Mars with introductory remarks by its producer/director/writer, Blaine Baggett, Director, Office of Communication and Education, JPL, about Mariner 3 and 4 missions to Mars embedded within his Von Karman lecture.
00:38:50you can see them "moving" (could be Mariner 3 or 4):
I struck out with my previous question so I'll try again.
What are these large circular 4-vane structures on the sides of NOAA-19 - the satellite that "fell down"?
They remind me of adjustable air vents but I have a feeling that's not quite right.
You can see them from another angle here.
Spacecraft rotated for better view: